Lecture 10: Locations

Question 1

What are the different ways of determining a users location?

Answer 1

• GPS/GNSS
• Network
• WiFi

Question 2

How does GPS/GNSS work?

Answer 2

Uses satellite positioning to determine an exaction location

power expensive

Question 3

How does network location work?

Answer 3

Provides an approximation of the users location using the location of a nearby cellular network tower

Question 4

How does WiFi location work?

Answer 4

Uses an IP address lookup to check the approximate location of the user

Question 5

What are the 2 types of location permissions?

Answer 5

• COARSE
• FINE

Question 6

What are FINE permissions?

Answer 6

Precision determined by GPS

Quoted accuraxy of +/- 50m

Question 7

What are COARSE permissions?

Answer 7

Precision determined by WiFi or Cellular Network

Quoted accuracy of +/- 3km^2

Question 8

What is the downside to using GPS location?

Answer 8

Its very battery intensive and typically slow

Question 9

What are the 2 practical problems you should consider when talking about location?

Answer 9

• How accurate do we need to be?
• Does the user have a choice?

Question 10

How does modern android allow users to have a choice on what location permissions they use?

Answer 10

Allows the user to select either

• Precise
• Approximate

location services at runtim

Question 11

What is the Fused Location Provide?

Answer 11

An API for fetching location data
Designed to handle all forms of location request (FINE or COARSE) with any location hardware (GPS, Network, WiFi)

Question 12

Why use the Fused Location Provider?

Answer 12

More efficient use of location data and battery

Question 13

How does Fused Location Provider save battery?

Answer 13

Minimizes the number of location request made and the amount of time location hardware is used for

Does this by re-using location requests made previously by other maps

Question 14

What are the downsides of fused location provider?

Answer 14

Doesn’t case too much about minute-to-minute accuracy

Location refresh rate is tied to when other apps force a location update

Question 15

In order to use the FusedLocationProvider we have to declare a __ of the provider

Answer 15

client

Question 16

What are the 2 notable methods that the client uses?

Answer 16

• getLastLocation()
• getCurrentLocation()

Question 17

What is getLastLocation()

Answer 17

A simple read-only request for the last known location
Location can be very stale

Question 18

What is getCurrentLocation()

Answer 18

Intelligently cache location data and only force an updated request when the last location data is considered to old

Question 19

Fused provider allows you to assign a ___ to each__ you make

Answer 19

• priority
• location request

Question 20

What are the location priority levels?

Answer 20

• PRIORITY_HIGH_ACCURACY
• PRIORITY_BALANCED_POWER_ACCURACY
• PRIORITY_LOW_POWER
• PRIORITY_NO_POWER

Question 21

What is the best way to actively track the user

Answer 21

Use the requestLocationUpdates() method on a FusedLocationProviderClient object to request regular location updates on a fixed time interval

Question 22

How does the requestLocationUpdates() method work?

Answer 22

Takes parameters for the request and includes a callback method

every n time interval the callback method is called and passes the updated location variable containing the current location data

Question 23

What are some of the things a location object holds?

Answer 23

longitude, latitude, altitude, compass, bearing, GPS satellite time